During borehole forming operations using a rotary drilling rig, it is customary to employ at least one, and usually several, series connected stabilizers. The stabilizers are generally placed in close proximity to the drill bit and form the dual function of reaming the borehole true while at the same time causing the drill bit to make the hole straighter.
A crooked borehole is undesirable for the reason that any subsequent running of a tool string or piping thereinto must follow a tortuous path which imposes undesirable bending moments into the downhole located equipment.
Various different stabilizers have been proposed in the prior art and include U.S. Pats. Nos. 3,052,310; 2,911,195; 2,872,159; 2,589,534; 2,607,561; and 1,590,422. These various different prior art tools represent but a few of the many stabilizers available to the oil industry. However, the means by which the cutting element or cutting blade is attached to the main stabilizer body is inadequate, and from time to time a blade will inadvertently loosen and fall to the bottom of the borehole. The blade has a very hard cutting edge or face formed thereon; and accordingly, the expensive drill bit is ruined when an attempt is made to "drill-up" the lost blade. Therefore, the blade, along with the various different associate parts employed to attach the blade to the body, must be fished from the borehole. A fishing job, especially on deep wells, is extremely expensive and is considered catastrophic in the science of forming boreholes.
Accordingly, it would be desirable to have made available a stabilizer apparatus having cutting blades removably affixed thereto which could not, under any circumstances, inadvertently part from the main body and fall to the bottom of the borehole. This desirable expedient would enable the massive main body of the stabilizer to be used again and again with only the relatively less expensive stabilizer blades being replaced from time to time. Such a desirable expedient is the subject of this invention.